— PHYS 375: Lab 11 – Logic gates –PurposesBuild and use logic gates.1 Diode-based logicsBuild the circuit shown in Figure 1 (part a).1. Explain how the circuit constitutes a variable voltage divider.2. For all possible combination of switches states (open/close) measure Va, Vband Voutusing a digitalmulti-meter. Gather your results in a table.3. Use the LED system shown in Figure b b to measure the logical level of Va, Vband Voutagain for allpossible combination o f switches states. LED on corresponds to TRUE (or 1) and off to FALSE(or 0). Make a truth table.(a)+5 VVout(b)Vin1 kW330 WFigure 1: Circuit for part 1.2 TTL NANDBuild the circuit shown in Figure 2 using a 74LS00 NAND gate. The g ate need an external voltage supplyvcc= 5 V (see instr uctor explanation).1. For all possible combination of sw itches r e c ord Va, Vband Voutusing a digital multimeter.2. or all possible combination of switches measure the logic levels with the diode probe system usedin the previous circuit.1+5 VVout1 kWVAVBFigure 2: Circuit for part 2.3. Close both s witches and connect a 1 MΩ r e sistor between the output and group measure Voutanddeduce Iout.4. Redo last step for 10 k, 1k, 470, 220 and 100 Ω. Plot Voutversus Ioutand discuss the plot.3 A TTL circuitBuild the circuit shown in Figure 3. using two 74lS00 NAND gates.1. Measure the truth table with the diode probe2. Record the voltages VAVBand Voutfor all the possible case of switches states.3. Deduce the logical operation achieved by this circuit.+5 VVout1 kWVAVBFigure 3: Circuit for part
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